Alternating-current rectifier.



T. A. EDISON.

ALTERNATING CURRENT RECTIFIER- AEPLlcATloN FILED DEc.a0,19|\.

1,221,981 Patented Apr. 10,1917.

2 SHEETS-SHEET l.

ffy.;

T. A. EDISON.

ALTERNATING CURRENT RECTIFIER.

APPLICATIONAHLED 0120.30. 19H.

1,221,981 Patented Apr. 10, 1917.

2 SHEETS-SHEET 2.

UNITED STATES PATENT OFFICE.

THOMAS A. EDISON, 0F LLEWELLYN PARK, WEST ORANGE, NEW JERSEY, ASVSIGNOBT0 NEW JERSEY PATENT COMPANY, 0F WEST ORANGE, NEW JERSEY, A CORPORA-TION 0F NEW JERSEY.

ALTEBNATING-CURRENT BEQTIFIEB.

Speeication of Letters Patent.

Patented Apr. 10, 1917.

Application led December 30, 1911. Serial No. 668,811.

To all whom t may concern: c

Be it known that I, THOMAS A. EDISON, a citizen of the United States,and a resident of Llewellyn Park, West Orange, Essex county, New Jersey,have invented certain new and useful Improvements in Alternating-CurrentRectifiers, of which the followingis a specification.

y invention relates to alternating current rectifiers and moreparticularly to that type of such rectifiers in which vibrating contactsare employed to open and close a circuit or circuits connected to asource of alternating current and to a direct current translating deviceor devices in such a manner as to cause the current impulses to passinto the direct current translating device or devices in one directiononly.

The usefulness of rectifiers of this type as hitherto constructed hasbeen materially limited by the small current-carrying capacity of theapparatus and by their inability to operate successfull on any but lowvoltage circuits, because o sparking and sticking of contacts. Myinvention has for its object the provision of simple, efficient andcompact rectifying devices in which these and other difiiculties andobjections are overcome.

In one aspect, my invention consists in a rectifying unit or units, eachhaving a plurality of armatures capable of vibration and adapted to openand close a circuit or circuits and means for causing the armatures tovibrate in synchronism with the alternating current to be rectified.Preferably, the armatures are capable of independent movement and areactuated by a single coil.v In my improved rectifiers I secure theadvantages of compactness, and of small inertia in the vibrating partsand consequent sensitiveness of operation in following the changes ofcurrent in the alternating current circuit. I may connect the contactscarried by the armatures in parallel, series, or series-parallel, andthe armatures preferably form parts of the electrical circuits. Theparallel connection affords a plurality of 'current conducting pathsthrough the rectifying unit, and a large current-carrying capacity isthus secured. The series connection affords a plurality of breaks inseries in a single unit, whereby sparking is reduced and the apparatusis rendered capable of rectifying currents of relatively high voltage.The

series-parallel connection combines theadv antagcs of the series andparallel connections.

In another aspect, my invention.. consists in the employment of contactmembers having relativel large contact surfaces, one or both of eachpair of coperating contact members being preferably of carbon. By theuse of contacts of this character, the current carrying capacity of eachrectifying unit is increased, sticking of contacts is pre'- vented, andsparking is reduced.

My invention consists also in the details of construction andcombinations of parts hereinafter described more fully and claimed.

In the drawin which accompany and form a part of this specification-Figure 1 is a side elevation partly insection of one embodiment of myimproved rectifier; l

Fig. 2 is a section taken on the line 2-2 of Fig. 1;

Fig. 3 is a diagrammatic view showing a system in which my improvedrectifier is adapted to be used, and in which the rectifier is connectedto an alternating current circuit for supplying iini-directional currentto a storage battery;

Fig. 4 is a plan view of a modied form of my improved rectifier;

Fig. 5 is a plan view of another modification of the same; and

Fig. 6 is a section taken on the line 6 6 of Fig.

In the embodiment of my invention which is illustrated in Figs. l, 2,and 3, I provide a magnet l which is preferably a permanent magnethaving an almost completely closed magnetic circuit. In the gap betweenthe north and south poles of the magnet 1, two or more armatures 2 and3, of magnetic material and preferably soft iron, are located.Surrounding the armatures 2 and 3 an actuating coil 4 is provided. Themagnet l, armatures 2 and 3 and coil 4 are supported in any suitablemanner as by means of a frame or base 5 of conductive material. Thearmatures 2 and 3 are mounted so as to be capable of vibration in thegap of the magnet l, as for example, by being pivotally mounted upon apivot 6 of conductive material supported in the frame 5. The armatures 2and 3 are preferably so mounted as `The stationary contact 9 and thestop to be capable of independent movement. The armatures 2 and 3 areprovided with suitable contacts 7 and 8 adapted to coperate with astationary contact 9. The contacts 7 and 8 have relatively large contactsurfaces and are preferably made of carbon. The carbon contacts 7 and 8may be mounted upon or secured to the armatures 2 and 3 in any suitablemanner, as for example, by screws 7 and 8 extended through the contacts7 and 8 and threaded into the ends of the armatures 2 and 3. Thestationary contact 9 has a relatively large Contact surface adapted tocoperate with the contacts 7 and 8, and is preferably made of conductingmetal, such as copper or brass, but may be made of carbon. Thestationary contact 9 is preferably adjustably mounted upon the magnet 1,and is insulated therefrom by insulating members 10 and 11 andadjustably secured thereto vby means of a screw 12. The stationaryContact 9 is provided with a screw or binding post 13 for connecting thecontact in a circuit. Gbviously, the stationary contact 9 may consist ofa-plurality of contacts suitably connected together. A stop 14 ofnon-magnetic material and preferably adjustably mounted upon the magnet1 is provided to limit the backward movement of the armatures 2 and 3and to keep them from sticking to the pole of the ma et. 14 arepreferably so adjusted that the amplitude of movement of the vibratingcontacts is very small, for example, from tive to ten onethousandths ofan inch. A binding post 15 is provided on the base 5. The armatures 2and 3 are in electrical connection with ,the base 5 and its binding post15 through the pivot 6 and through flexible wires 16 and 17 connectingthe armatures 2 and 3 respectively vto the base 5. The wires 16 and 17are secured to the armatures 2 and 3 near their pivotal axes, so as tointerfere.

as little as possible with their freedom of vibration.

Referring particularly to Fig. 3, alternating currentV mains are shownat 20 and 21. @ne terminal of the coil 4 is connected to one of thealternating current mains 2O by a conductor 22, and the other terminalof the coil .4 is connected to the other main 21 by the conductor 23. Anadjustable condenser l24 is preferably connected in series with the coil4 and is shown inserted in the conductor 23. rlfhe stationary contact 9is connected to one side of the alternating current circuit 21 by meansof conductor 25, and the frame of the device is connected to the otherside of the alternating current circuit 20 by means of the conductor 26.1n the circuit containing the contact 9, the direct current translatingdevice or devices are connected. ll have illustrated as such a device astorage battery 27 and also Yan more, when the upper ends of thearmatures are of north polarity, the south pole of the permanent magnetis strengthened and the north pole weakened, and when the upper ends ofthe armatures are of south polarity, the north pole of the permanentmagnet is strengthened and the south pole weakened. As a result, thearmatures are vibrated in synchronism with the alternating currentflowing through the coil 4. When the contacts 7 and 8 are in contactwith the contact 9 a circuit is established from the alternating currentmain 21 through the conductor 25 and contact 9, Where the circuitdivides, one branch of it extending through the contact 7, armature 2,to the frame 5 and binding post 15, and vthe other branch extendingthrough the contact 8, armature 3 and the frame 5 to binding post 15,then from the binding post 15 to the conductor 26, storage battery orother direct current translating device 27, rheostat 28, to the otherside of the alternating current circuit 20. This condition of affairscontinues during one half wave of the alternating current. During thesucceeding half wave, the circuit is broken at the contacts 7, 8 and 9.`In this manner, uni-directional current is supplied to the storagebattery or other direct current translating device 27. The adjustablecondenser 24 in series with the coil 4 is em- ".ployed to advance thephase of the current in the coil in order to compensate for the inertiaof the armatures and to cause the circuit to be broken at the propertimes to avoid sparking.

By the provision of a plurality of comparatively light armatures,capable of independent vibration, am enabled to secure greatsensitiveness of operation, and the armatures in their movements followclosely the variations of current in the line and the Coil 4. Byconnecting the contacts and armatures in parallel, I am enabled tosecure a large current-carrying capacity in the apparatus. 1

llnstead of connecting the contacts in parallel, ll may connect them inseries as is illustrated in Fig. 4, or 'in series-parallel as isillustrated in Figs. 5 and 6.

The modification illustrated in Fig. 4 differs from that shown in Figs.1 and 2 in having two stationary contacts 9a and 9* instead of thesingle contact 9 shown in Figs.l 1 and 2. The two contacts 9a and 9b areinsulated from each other and from the magnet 1. rlihe contacts 9 and 9bare adapt amature 3, contact 8, and contact 9" to binding post 13". Inthis modification each time the circuit is broken there are at least twobreaks in series.` The drop in potential across each of the breaks isthus decreased, and\the apparatus is adapted to be used on relativelyhigh voltage circuits without injurious sparking.

In the modification of my improved rectifier illustrated in Figs. 5 and6, magnets 30 and 31 are provided, which are preferably permanentmagnets of the same form as the magnet shown in Figs. 1 and 2. In thegap of the magnet 30 armatures 32, 33 and 34 are located, and in the gapof the magnet 31 armatures 35, 36 and 37 are located. The magnet 30 ismounted upon a frame or base 38 of conductive material, and the magnet31 is mounted upon a frame or base 39 of conductive material. Thearmatures 32, 33 and 34 are mounted so as to be capable of vibration inthe gap of the magnet 30, and

- preferably independently of each other, as

for example, by mounting the same upon a pivot 40 of conductive materialsupported in the frame 38, and the armatures 35, 36 and 37 are mountedso as to be capable of vibration in the gap of the magnet 31, andreferably independently of each other, as or example, by mountlng thesame upon the pivot 41 of conductive material supportil ed in the frame39. The armatures 32, 33 and 34 are provided with contacts 42, 43 and 44respectively, and the armatures 35, 36 and 37 are provided with contacts45, 46 and 47 respectively. The contacts 42, 43, 44, 45, 46 and 47 haverelatively large contact surfaces and are preferably of carbonand aremounted on their respective armatures in any suitable manner. Thecontacts 42, 43 and 44 are adapted to coperate with the stationarycontact 65, preferably adjustably mounted upon one pole of the magnet30, and the contacts 45, 46 and 47 are adapted to coperate with thestationary contact 66, preferably adjustably mounted upon one pole ofthe magnet 31. The contacts 65 and 66 have relatively large conductingsurfaces and are preferably made of conducting metal such as brass orcopper, but may be made of carbon. The contacts 65 and 66 are providedwith screws or binding posts 48 and 49 respectively to facilitate makingcircuit connections. An adjustable back stop 50 is provided for thearmatures 32, 33 and 34,

and an adjustable back stop 51 is provided for the armatures 45, 46 and47. An actuating coil 52 surrounds all of the armatures and may -besupported by the frames or bases 38 and 39. The frames 38 and 39 aremounted upon 'an insulating support 53. The armatures 32, 33 and 34 arein electrical connection with the frame 38 through the pivot 40, and inorder to secure good electrical connection, wires 54, 55 and 56connecting the armatures 32, 33 and 34 respectively to the frame 38 areprovided. The armatures 35, 36 and 37 are in electrical connection withthe frame 39 through the pivot 41, and wires 57, 58 and 59 areprovidedconnecting the armatures 35, 36 and 37 respectivel with theframe 39 in order to insure g electrical connection between thearmatures and the frame. The wires 54, 55, 56, 57, 58 and 59 are securedto the armatures near their pivotal axes so as to interfere as little aspossible with their freedom of vibration. The frame 38 is connected tothe contact 66 by the conductor 60. The frame 39 is provided with abinding post 61. In connecting up the modification shown in Figs. 4 and5, the coil 52 is connected either directly across the alternatingcurrent mains, or preferably in series with an adjustable condenser andacross the mains. The contact 65 is connected to one side of thealternating current circuit by means. of the screw or binding post 48,and

the binding post 61 is connected to the direct translating device towhich uni-directional current .is to be supplied. The other side of thedirect current translating device is connected to the other side of thealternating current circuit, preferably through an adjustable rheostat.The circuit through the rectifying device When the contacts are closedis as follows To contact 65, then dividing into three paths, the firstthrough the contact 42 and the armature 32 to the frame 38; the second,through the Contact 43, and the armature 33, to the frame 38; and thethird, through the contact 44 and the armature 34 to the frame 38; thenfrom the frame 38 through conductor 60 to the contact 66; at the contact66, the circuit again dividesv into three branches: the first, throughthe contact 45 and the armature 35 to the frame 39; the second, throughthe contact 46 and the armature 36 to the frame 39; the third, throughthe contact 47 and armature 37 to the frame 39; then from the frame 39through the binding post 61 to the direct current translating device.This condition of affairs continues during one half wave of thealternating current, and during the succeeding half Wave the circuit isbroken. In this manner uni-directional current is supplied to the directcurrent translating device.

The rectifier shown in Figs. 5 and 6 may also be modified by dispensingwith the binding post 61 and the connection 60, and

.before set forth are secured.

In the structure illustrated in Figs. 5 and 6, a simple seriesconnection may be obtained by replacing the armatures, 32, 33 and 34 bya single armature and the armatures 35,

` 36 and 37 by a single armature.

The kind of carbon I prefer to use for the contacts is graphitic 1ncharacter, and wherever I employ the Word carbon in the appended claims,I mean to include graphite.

Havin now described my invention, what I c aim and desire r,to protectby Letters Patent is as follows 1. In an alternating current rectier,

means :for producing magnetic link, a plurality. of armatures adapted tovibrate in the field of said fluir and provided with contacts foropening and closing a circuit, the said contacts being connected inseries when in circuit-closing position, and an actuating coilsurrounding said armatures, substantially as described.

2. In an alternating current rectifier, a

v plurality of armatures provided with conan actuating coil for thearmatures, substantially as described.

3. In an alternating current rectifier, a

plurality of armatures capable of independent vibration and' providedwith contacts for opening and closing` a circuit, the said contactsbeing connected in series-parallel when in circuit closing position, andan actuating coil for the armatures, as described.

et. In an alternating current rectifier, a plurality of armaturesprovided with contacts for opening and closing a circuit; the saidcontacts being connected in` seriesparallel when in circuit closingposition, and an actuating coil surrounding the armatures, substantiallyas' described.

5. In an alternating current rectifier, a plurality of armatures capableof independ ent movement and provided with contacts for opening andclosing a circuit, the said contacts being connected in series-parallelwhen in circuit closin position, and an actuating coil surroun ing thearmatures, substantlally as described.

rIhis specification signed and witnessed. this 12th day of December,1911.

` THOS. A. EDISON. Witnesses:

HENRY LANAHAN, ANNA R. KLEHM.

It is hereby certified that in Letters Patent No. 1,221,981, grantedApril l0,y

i917, upon the application oi Thomas A. Edison, of Llewellyn Park, WestOrange, Y,

New Jersey, for an improvement "Alternating-Current Rectiiers, an errorappears in the printed specicationrequiring correction as follows: Page3, line 97, 4

after the Word "direct insert the Word current; and that the saidLetters Patent 'should be read with this correction therein that thesame may conform to the record otthe caso in the Patent @Hice tanningiva-acs.

n. r. Wnrrnnnan,

Acting Commissioner cj Patents.

